<!DOCTYPE html>
<html lang="en">
	<head>
		<title>three.js webgl - materials - custom blending</title>
		<meta charset="utf-8">
		<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
		<style>
			body {
				margin: 0px;
				background-color: #111;
				overflow: hidden;
				font-family: arial;
			}

			.menu { color: #fff; font-weight: bold; font-size: 12px; z-index: 100; width: 75px; position: absolute; top: 0px; padding: 16px; }
			.menu img, .menu canvas { width: 75px; margin: 10px 0 }

			#images { background: rgba(0,0,0,0); left: 0px; }
			#backgrounds { background: rgba(0,0,0,0.0); left: 107px; }
			#labels { background: rgba(0,0,0,0.75); left: 214px; width: 100px }

			.lbl { color: #fff; z-index: 150; float:left; padding: 0.25em; width: 75px; display: block  }
			#lbl_dst { background:#800; }
			#lbl_src { background:green; }

			.btn { background: darkorange; width: 100px; cursor: pointer }

			#btn_sub { background: transparent }
			#btn_rsub { background: transparent }
			#btn_min { background: transparent }
			#btn_max { background: transparent }

			#btn_pre { background: transparent }

			#btn_max, #btn_nopre { margin-bottom: 2em }
		</style>
	</head>
	<body>

		<div id="images" class="menu">
			Foreground
			<a id="img_0" href="#"><img src="textures/disturb.jpg" /></a>
			<a id="img_1" href="#"><img src="textures/sprite0.jpg" /></a>
			<a id="img_2" href="#"><img src="textures/sprite0.png" /></a>
			<a id="img_3" href="#"><img src="textures/lensflare/lensflare0.png" /></a>
			<a id="img_4" href="#"><img src="textures/lensflare/lensflare0_alpha.png" /></a>
			<a id="img_5" href="#"><img src="textures/sprites/ball.png" /></a>
			<a id="img_6" href="#"><img src="textures/sprites/snowflake7_alpha.png" /></a>
		</div>

		<div id="backgrounds" class="menu">
			Background
			<a id="bg_0" href="#"><img src="textures/disturb.jpg" /></a>
			<a id="bg_1" href="#"></a>
			<a id="bg_2" href="#"></a>
			<a id="bg_3" href="#"><img src="textures/crate.gif" /></a>
			<a id="bg_4" href="#"><img src="textures/lava/lavatile.jpg" /></a>
			<a id="bg_5" href="#"><img src="textures/water.jpg" /></a>
			<a id="bg_6" href="#"><img src="textures/lava/cloud.png" /></a>
		</div>

		<div id="labels" class="menu">
			Equation<br/><br/>
			<div class="lbl btn" id="btn_add">Add</div>
			<div class="lbl btn" id="btn_sub">Subtract</div>
			<div class="lbl btn" id="btn_rsub">ReverseSubtract</div>
			<div class="lbl btn" id="btn_min">Min</div>
			<div class="lbl btn" id="btn_max">Max</div>

			Premultiply alpha<br/><br/>
			<div class="lbl btn" id="btn_pre">On</div>
			<div class="lbl btn" id="btn_nopre">Off</div>

			Labels<br/><br/>
			<div class="lbl" id="lbl_src">Source</div>
			<div class="lbl" id="lbl_dst">Destination</div>
		</div>

		<script type="module">

			import * as THREE from '../build/three.module.js';

			let camera, scene, renderer;

			let materialBg;
			const materials = [];

			const mapsPre = [];
			const mapsNoPre = [];

			let currentMaps = mapsNoPre;
			let currentIndex = 4;

			init();
			animate();

			function init() {

				// CAMERA

				camera = new THREE.PerspectiveCamera( 80, window.innerWidth / window.innerHeight, 1, 1000 );
				camera.position.z = 700;

				// SCENE

				scene = new THREE.Scene();

				// TEXTURE LOADER

				const textureLoader = new THREE.TextureLoader();

				// BACKGROUND IMAGES

				const canvas1 = document.createElement( 'canvas' );
				const ctx1 = canvas1.getContext( '2d' );
				canvas1.width = canvas1.height = 128;
				ctx1.fillStyle = '#eee';
				ctx1.fillRect( 0, 0, 128, 128 );
				ctx1.fillStyle = '#999';
				ctx1.fillRect( 0, 0, 64, 64 );
				ctx1.fillStyle = '#aaa';
				ctx1.fillRect( 32, 32, 32, 32 );
				ctx1.fillStyle = '#999';
				ctx1.fillRect( 64, 64, 64, 64 );
				ctx1.fillStyle = '#bbb';
				ctx1.fillRect( 96, 96, 32, 32 );

				document.getElementById( 'bg_1' ).appendChild( canvas1 );

				const canvas2 = document.createElement( 'canvas' );
				const ctx2 = canvas2.getContext( '2d' );
				canvas2.width = canvas2.height = 128;
				ctx2.fillStyle = '#444';
				ctx2.fillRect( 0, 0, 128, 128 );
				ctx2.fillStyle = '#000';
				ctx2.fillRect( 0, 0, 64, 64 );
				ctx2.fillStyle = '#111';
				ctx2.fillRect( 32, 32, 32, 32 );
				ctx2.fillStyle = '#000';
				ctx2.fillRect( 64, 64, 64, 64 );
				ctx2.fillStyle = '#222';
				ctx2.fillRect( 96, 96, 32, 32 );

				document.getElementById( 'bg_2' ).appendChild( canvas2 );

				const mapBg0 = new THREE.CanvasTexture( canvas1 );
				mapBg0.wrapS = mapBg0.wrapT = THREE.RepeatWrapping;
				mapBg0.repeat.set( 128, 64 );

				const mapBg1 = new THREE.CanvasTexture( canvas2 );
				mapBg1.wrapS = mapBg1.wrapT = THREE.RepeatWrapping;
				mapBg1.repeat.set( 128, 64 );

				const mapBg2 = textureLoader.load( 'textures/disturb.jpg' );
				mapBg2.wrapS = mapBg2.wrapT = THREE.RepeatWrapping;
				mapBg2.repeat.set( 8, 4 );

				const mapBg3 = textureLoader.load( 'textures/crate.gif' );
				mapBg3.wrapS = mapBg3.wrapT = THREE.RepeatWrapping;
				mapBg3.repeat.set( 32, 16 );

				const mapBg4 = textureLoader.load( 'textures/lava/lavatile.jpg' );
				mapBg4.wrapS = mapBg4.wrapT = THREE.RepeatWrapping;
				mapBg4.repeat.set( 8, 4 );

				const mapBg5 = textureLoader.load( 'textures/water.jpg' );
				mapBg5.wrapS = mapBg5.wrapT = THREE.RepeatWrapping;
				mapBg5.repeat.set( 8, 4 );

				const mapBg6 = textureLoader.load( 'textures/lava/cloud.png' );
				mapBg6.wrapS = mapBg6.wrapT = THREE.RepeatWrapping;
				mapBg6.repeat.set( 2, 1 );

				// BACKGROUND

				materialBg = new THREE.MeshBasicMaterial( { map: mapBg1 } );

				const meshBg = new THREE.Mesh( new THREE.PlaneGeometry( 4000, 2000 ), materialBg );
				meshBg.position.set( 0, 0, - 1 );
				scene.add( meshBg );

				// FOREGROUND IMAGES

				const images = [ 'textures/disturb.jpg',
					'textures/sprite0.jpg',
					'textures/sprite0.png',
					'textures/lensflare/lensflare0.png',
					'textures/lensflare/lensflare0_alpha.png',
					'textures/sprites/ball.png',
					'textures/sprites/snowflake7_alpha.png' ];

				for ( let i = 0; i < images.length; i ++ ) {

					const map = textureLoader.load( images[ i ] );
					mapsNoPre.push( map );

					const mapPre = textureLoader.load( images[ i ] );
					mapPre.premultiplyAlpha = true;
					mapPre.needsUpdate = true;
					mapsPre.push( mapPre );

				}

				// FOREGROUND OBJECTS
				const src = [
					{ name: 'Zero', constant: THREE.ZeroFactor },
					{ name: 'One', constant: THREE.OneFactor },
					{ name: 'SrcColor', constant: THREE.SrcColorFactor },
					{ name: 'OneMinusSrcColor', constant: THREE.OneMinusSrcColorFactor },
					{ name: 'SrcAlpha', constant: THREE.SrcAlphaFactor },
					{ name: 'OneMinusSrcAlpha', constant: THREE.OneMinusSrcAlphaFactor },
					{ name: 'DstAlpha', constant: THREE.DstAlphaFactor },
					{ name: 'OneMinusDstAlpha', constant: THREE.OneMinusDstAlphaFactor },
					{ name: 'DstColor', constant: THREE.DstColorFactor },
					{ name: 'OneMinusDstColor', constant: THREE.OneMinusDstColorFactor },
					{ name: 'SrcAlphaSaturate', constant: THREE.SrcAlphaSaturateFactor }
				];

				const dst = [
					{ name: 'Zero', constant: THREE.ZeroFactor },
					{ name: 'One', constant: THREE.OneFactor },
					{ name: 'SrcColor', constant: THREE.SrcColorFactor },
					{ name: 'OneMinusSrcColor', constant: THREE.OneMinusSrcColorFactor },
					{ name: 'SrcAlpha', constant: THREE.SrcAlphaFactor },
					{ name: 'OneMinusSrcAlpha', constant: THREE.OneMinusSrcAlphaFactor },
					{ name: 'DstAlpha', constant: THREE.DstAlphaFactor },
					{ name: 'OneMinusDstAlpha', constant: THREE.OneMinusDstAlphaFactor },
					{ name: 'DstColor', constant: THREE.DstColorFactor },
					{ name: 'OneMinusDstColor', constant: THREE.OneMinusDstColorFactor }
				];

				const geo1 = new THREE.PlaneGeometry( 100, 100 );
				const geo2 = new THREE.PlaneGeometry( 100, 25 );

				for ( let i = 0; i < dst.length; i ++ ) {

					const blendDst = dst[ i ];

					for ( let j = 0; j < src.length; j ++ ) {

						const blendSrc = src[ j ];

						const material = new THREE.MeshBasicMaterial( { map: currentMaps[ currentIndex ] } );
						material.transparent = true;

						material.blending = THREE.CustomBlending;
						material.blendSrc = blendSrc.constant;
						material.blendDst = blendDst.constant;
						material.blendEquation = THREE.AddEquation;

						const x = ( j - src.length / 2 ) * 110;
						const z = 0;
						const y = ( i - dst.length / 2 ) * 110 + 50;

						const mesh = new THREE.Mesh( geo1, material );
						mesh.position.set( x, - y, z );
						mesh.matrixAutoUpdate = false;
						mesh.updateMatrix();
						scene.add( mesh );

						materials.push( material );

					}

				}

				for ( let j = 0; j < src.length; j ++ ) {

					const blendSrc = src[ j ];

					const x = ( j - src.length / 2 ) * 110;
					const z = 0;
					const y = ( 0 - dst.length / 2 ) * 110 + 50;

					const mesh = new THREE.Mesh( geo2, generateLabelMaterial( blendSrc.name, 'rgba( 0, 150, 0, 1 )' ) );
					mesh.position.set( x, - ( y - 70 ), z );
					mesh.matrixAutoUpdate = false;
					mesh.updateMatrix();
					scene.add( mesh );

				}

				for ( let i = 0; i < dst.length; i ++ ) {

					const blendDst = dst[ i ];

					const x = ( 0 - src.length / 2 ) * 110 - 125;
					const z = 0;
					const y = ( i - dst.length / 2 ) * 110 + 165;

					const mesh = new THREE.Mesh( geo2, generateLabelMaterial( blendDst.name, 'rgba( 150, 0, 0, 1 )' ) );
					mesh.position.set( x, - ( y - 120 ), z );
					mesh.matrixAutoUpdate = false;
					mesh.updateMatrix();
					scene.add( mesh );

				}

				// RENDERER

				renderer = new THREE.WebGLRenderer();
				renderer.setPixelRatio( window.devicePixelRatio );
				renderer.setSize( window.innerWidth, window.innerHeight );

				renderer.domElement.style.position = 'absolute';
				renderer.domElement.style.left = '215px';

				document.body.appendChild( renderer.domElement );

				// EVENTS

				window.addEventListener( 'resize', onWindowResize );

				addImgHandler( 'img_0', 0 );
				addImgHandler( 'img_1', 1 );
				addImgHandler( 'img_2', 2 );
				addImgHandler( 'img_3', 3 );
				addImgHandler( 'img_4', 4 );
				addImgHandler( 'img_5', 5 );
				addImgHandler( 'img_6', 6 );

				addBgHandler( 'bg_0', mapBg2 );
				addBgHandler( 'bg_1', mapBg0 );
				addBgHandler( 'bg_2', mapBg1 );
				addBgHandler( 'bg_3', mapBg3 );
				addBgHandler( 'bg_4', mapBg4 );
				addBgHandler( 'bg_5', mapBg5 );
				addBgHandler( 'bg_6', mapBg6 );

				addEqHandler( 'btn_add', THREE.AddEquation );
				addEqHandler( 'btn_sub', THREE.SubtractEquation );
				addEqHandler( 'btn_rsub', THREE.ReverseSubtractEquation );
				addEqHandler( 'btn_min', THREE.MinEquation );
				addEqHandler( 'btn_max', THREE.MaxEquation );

				addPreHandler( 'btn_pre', mapsPre );
				addPreHandler( 'btn_nopre', mapsNoPre );

			}

			//

			function addImgHandler( id, index ) {

				const el = document.getElementById( id );

				el.addEventListener( 'click', function () {

					for ( let i = 0; i < materials.length; i ++ ) {

						materials[ i ].map = currentMaps[ index ];

					}

					currentIndex = index;

				} );

			}

			function addEqHandler( id, eq ) {

				const el = document.getElementById( id );

				el.addEventListener( 'click', function () {

					for ( let i = 0; i < materials.length; i ++ ) {

						materials[ i ].blendEquation = eq;

					}

					document.getElementById( 'btn_add' ).style.backgroundColor = 'transparent';
					document.getElementById( 'btn_sub' ).style.backgroundColor = 'transparent';
					document.getElementById( 'btn_rsub' ).style.backgroundColor = 'transparent';
					document.getElementById( 'btn_min' ).style.backgroundColor = 'transparent';
					document.getElementById( 'btn_max' ).style.backgroundColor = 'transparent';

					el.style.backgroundColor = 'darkorange';

				} );

			}

			function addBgHandler( id, map ) {

				const el = document.getElementById( id );
				el.addEventListener( 'click', function () {

					materialBg.map = map;

				}	);

			}

			function addPreHandler( id, marray ) {

				const el = document.getElementById( id );
				el.addEventListener( 'click', function () {

					currentMaps = marray;

					for ( let i = 0; i < materials.length; i ++ ) {

						materials[ i ].map = currentMaps[ currentIndex ];

					}

					document.getElementById( 'btn_pre' ).style.backgroundColor = 'transparent';
					document.getElementById( 'btn_nopre' ).style.backgroundColor = 'transparent';

					el.style.backgroundColor = 'darkorange';

				} );

			}

			//

			function onWindowResize() {

				renderer.setSize( window.innerWidth, window.innerHeight );

				camera.aspect = window.innerWidth / window.innerHeight;
				camera.updateProjectionMatrix();

			}

			//

			function generateLabelMaterial( text, bg ) {

				const canvas = document.createElement( 'canvas' );
				const ctx = canvas.getContext( '2d' );
				canvas.width = 128;
				canvas.height = 32;

				ctx.fillStyle = bg;
				ctx.fillRect( 0, 0, 128, 32 );

				ctx.fillStyle = 'white';
				ctx.font = '12pt arial bold';
				ctx.fillText( text, 8, 22 );

				const map = new THREE.CanvasTexture( canvas );

				const material = new THREE.MeshBasicMaterial( { map: map, transparent: true } );
				return material;

			}

			function animate() {

				requestAnimationFrame( animate );

				const time = Date.now() * 0.00025;
				const ox = ( time * - 0.01 * materialBg.map.repeat.x ) % 1;
				const oy = ( time * - 0.01 * materialBg.map.repeat.y ) % 1;

				materialBg.map.offset.set( ox, oy );

				renderer.render( scene, camera );

			}

		</script>

	</body>
</html>
